All such, then, wherever they may be, are true priests, observe the mass aright and also obtain by it what they desire. For faith must do everything. It alone is the true priestly office and permits no one else to take its place. Therefore all Christians are priests; the men, priests, the women, priestesses, be they young or old, masters or servants, mistresses or maids, learned or unlearned. Here there is no difference, unless faith be unequal. Again, all who do not have such faith, but presume to make much of the mass as a sacrifice, and perform this office before God, are figure-heads. They observe mass outwardly and do not themselves know what they are doing, and cannot be well pleasing to God. For without true faith it is impossible to please Him, as St. Paul says in Hebrews xi. [Heb. 11:6] Now there are many who, hidden in their hearts, have such true faith, and themselves know not of it; many there are who do not have it, and of this, too, they are unaware. [Sidenote: Masses for the Dead] 39. It has become a wide-spread custom to found masses for the dead, and many books have been written about it. If we ask now, Of what benefit are the masses celebrated for the souls which are kept in purgatory? the answer is: What is custom! God's Word must prevail and remain true, to wit, that the mass is nothing else than a testament and sacrament of God, and cannot be a good work or a sacrifice, although it may be taken to include sacrifice and good works, as was said above.[21] There is no doubt, therefore, that whoever observes mass without the faith aforementioned benefits neither himself nor any one else. For the sacrament in itself, without faith, does nothing; nay, God Himself, Who indeed doeth all things, does and can do good to no one unless he firmly believes Him; how much less can the sacrament. It is easy to say, a mass is effective whether it be performed by a pious or a wicked priest, that it is acceptable opere operati, not opere operantis.[22] But to produce no other argument except that many say this, and it has become a custom, is poor proof that it is right. Many have praised pleasures and riches and have grown accustomed to them; that does not make them right; we should produce Scripture or reason for it. Therefore let us take heed lest we be made fools. I cannot conclude that the institution of so many masses and requiems can be without abuse, especially since all this is done as a good work and sacrifice by which to pay God, whereas in the mass there is nothing else than the reception and enjoyment of divine grace, promised and given us in His testament and sacrament.